[RFC PATCH 06/12] LoongArch: Implement ARCH_HAS_KERNEL_FPU_SUPPORT

From: Samuel Holland
Date: Fri Dec 08 2023 - 00:55:33 EST


LoongArch already provides kernel_fpu_begin() and kernel_fpu_end() in
asm/fpu.h, so it only needs to add kernel_fpu_available() and export
the CFLAGS adjustments.

Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
---

arch/loongarch/Kconfig | 1 +
arch/loongarch/Makefile | 5 ++++-
arch/loongarch/include/asm/fpu.h | 1 +
3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index ee123820a476..65d4475565b8 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -15,6 +15,7 @@ config LOONGARCH
select ARCH_HAS_CPU_FINALIZE_INIT
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_KCOV
+ select ARCH_HAS_KERNEL_FPU_SUPPORT if CPU_HAS_FPU
select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PTE_SPECIAL
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index 204b94b2e6aa..f5c4f7e921db 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -25,6 +25,9 @@ endif
32bit-emul = elf32loongarch
64bit-emul = elf64loongarch

+CC_FLAGS_FPU := -mfpu=64
+CC_FLAGS_NO_FPU := -msoft-float
+
ifdef CONFIG_DYNAMIC_FTRACE
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
CC_FLAGS_FTRACE := -fpatchable-function-entry=2
@@ -46,7 +49,7 @@ ld-emul = $(64bit-emul)
cflags-y += -mabi=lp64s
endif

-cflags-y += -pipe -msoft-float
+cflags-y += -pipe $(CC_FLAGS_NO_FPU)
LDFLAGS_vmlinux += -static -n -nostdlib

# When the assembler supports explicit relocation hint, we must use it.
diff --git a/arch/loongarch/include/asm/fpu.h b/arch/loongarch/include/asm/fpu.h
index c2d8962fda00..3177674228f8 100644
--- a/arch/loongarch/include/asm/fpu.h
+++ b/arch/loongarch/include/asm/fpu.h
@@ -21,6 +21,7 @@

struct sigcontext;

+#define kernel_fpu_available() cpu_has_fpu
extern void kernel_fpu_begin(void);
extern void kernel_fpu_end(void);

--
2.42.0